CLAVATA allowed 3D growth in land plants (Curr. Biol.)

Land plants had to acquire new ways to occupy the terrestrial environment, including the innovative shooting system with organs in a radial position. This new 3D form of growth was possible thanks to the capacity to rotate stem cells divisions through different orientation planes. In Arabidopsis the CLAVATA (CLV) and WUSCHEL (WUS) pathways regulate stem cell proliferation including cell fate, proliferation and growth. Whitewoods and co-workers searched for homologs of genes from the CLV pathway in green algae and land plants, finding only homologs of CLV3-like (CLE) and CLV1/BAM in early diverging bryophytes and all other land plants. Expression analysis of the homologs found in Physcomitrella showed that they were expressed during the 3D growth phase, and furthermore RNAi mutants of the genes had a defective 2D-3D growth transition. (Summary by Cecilia Vasquez-Robinet)  Curr. Biol. 10.1016/j.cub.2018.05.068